The present invention relates generally to faceplates for electrical equipment which provide electromagnetic shielding.
Network routers are electrical devices which transmit data packets between nodes on a network. Network routers are typically constructed to have multiple bays wherein each bay is constructed to receive a network module which routes network traffic. Each network module can handle a certain amount of traffic and the multiple bay structure allows a network router to be populated with a variable number of network modules to handle a variable amount of traffic. Examples of network routers are Cisco router models 2600, 3620 and 3640.
When a bay in a network router is left empty, then the opening in the front panel of the router must be covered with a faceplate. The opening must be covered to protect technicians from electrical shock from the voltages present within the router. Safety requirements, such as those promulgated by Underwriter""s Laboratories, also require that the faceplate be designed such that a tool is required to remove the faceplate to avoid manual contact with electrical voltages within the network router, which are typically in the range of 100-240 volts at 2 amps of current.
In addition, the faceplate must be conductive and must be electrically connected to the chassis of the network router to prevent electromagnetic interference (EMI) signals from escaping from the network router. Covering the opening also helps to maintain the proper air flow within the network router.
FIG. 1 illustrates a frontal view of an embodiment of a network router 10 with conventional faceplates 20A-C. For simplicity, only faceplate 20A is discussed in detail, but the detail discussion of faceplate 20A applies with equal weight to faceplates 20B-C.
Faceplate 20A includes ears 22A and 26A which each include a hole (not shown) to accommodate screws 24A and 28A, respectively. Screws 24A and 28A are threaded into screw holes (not shown) formed in frame 12 of network router 10 in order to fasten faceplate 20A to the router. Threaded screw holes 16D and 18D, associated with network bay opening 14D, are shown and there are similar bay openings and associated screw holes underlying each of faceplates 20A-C. Faceplate 20A also includes EMI clips 30 which are fastened along the periphery of faceplate 20A and make contact with the frame 12. Faceplate 20A also typically includes airflow holes (not shown) formed in the faceplate.
Faceplate 20A is generally formed using cold rolled steel, such as steel with an Aim Rockwell 30-T scale hardness level of 46-52 (hereinafter referred to as T-1), which is relatively inexpensive, heavy gauge, and easy to make and form. To form the conventional faceplate 20A, production starts with cold rolled T-1 steel which is then stamped to form air holes and bent to form upper and lower edges of the faceplate. Screw holes are then punched and tapped to accommodate screws 24A and 28A. The steps described can be performed in the same stamping machine resulting in relatively low production costs.
However, when cold rolled steel is used, EMI clips 30 must be included to provide sufficient electrical contact with the frame 12 of router 10 in order to absorb the electrical noise signals generated within the router which must be prevented from leaving the router housing. The clips 30 are typically made from a Beryllium-Copper (Bexe2x80x94Cu) alloy which is relatively expensive. The addition of clips 30 also results in an additional assembly step.
The attachment of the assembled faceplate 20A to router 10 further requires screws 24A and 28A, which represent an additional cost and an additional, relatively time consuming, assembly step. Also, removal of the faceplate when a network module is installed in the corresponding bay of router 10 requires removal of the screws which is time-consuming and represents an opportunity for the installing technician to lose the screws inside the router 10 among high voltage power busses.
Accordingly, a need remains for a structure and method for covering an opening in an unused bay of a piece of electrical equipment which is inexpensive, convenient and which prevents EMI signals from escaping from the electrical equipment.
An embodiment of a faceplate for covering an opening in an equipment bay, according to the present invention, includes a metallic planar body having first and second edges, the first and second edges opposing one another, a first flange extending from the first edge of the planar body along the plane of the planar body and a bracing tongue formed on the first flange and configured to engage a first edge of the opening. The faceplate also includes a second flange extending from the second edge of the planar body along the plane of the planar body, a cantilever beam having distal and proximal portions, the proximal portion being in communication with the second flange wherein the cantilever beam extends outward from the plane of the planar body and has a bias position, and a latching mechanism formed on an end of the cantilever beam which is distal to the planar body, wherein the latching mechanism is configured to hold a second edge of the opening against the second flange.
An embodiment of a method for producing a faceplate, according to the present invention, includes providing a sheet of conductive material and cutting the sheet to form first, second, third and fourth flanges. The method then calls for cutting the first flange to form a first strip of material and bending the first strip of material to form a bracing tongue. The method also includes cutting the second flange to form a second strip of material and bending the second strip of material to form a cantilever beam. The method then calls for bending the third flange by at least ninety degrees and bending the fourth flange by at least ninety degrees.
Another embodiment of a faceplate for covering an opening of an equipment bay, according to the present invention, includes conductive shielding means for covering the opening, bracing means for securing the shielding means against a first edge of the opening, and latching means for securing the shielding means against a second edge of the opening.
The foregoing and other objects, features and advantages of the invention will become more readily apparent from the following detailed description of a preferred embodiment of the invention which proceeds with reference to the accompanying drawings.